The present invention relates to a four-roller sheet bending machine.
Such machines usually comprise a driven upper roller and a driven lower roller and two non-driven side-rollers disposed on respectively opposite sides of the pair of nip rollers formed by the upper and lower rollers. There are forms of construction, in which at least the side-rollers are displaceably journalled and in which displacing means for each side-roller are hydraulically actuable. FIG. 1 of the accompanying drawing shows a schematic side elevation of a known machine of this kind. At the foot of a side cheek element 1 of the frame of the machine, hydraulic cylinders 2 are each fastened by means of bolts 3 passing through lugs 2a. A piston 4 is connected by a piston rod 5 with a bearing block 6, which is guided between guides 7 and 8. An end portion 9 of the bearing block 6 is constructed as a bearing for one end portion 10 of the left-hand side-roller shown in FIG. 1. The respective other end portion of the left-hand side-roller is similarly supported. Moreover, the right-hand side-roller in FIG. 1 is supported in the same manner as the left-hand side-roller. As one can see from FIG. 1, the minimum overall dimensions of the machine side cheek elements, namely the width b, and the height h, and thus also their weight and, of course, within certain limits, also their cost, are determined by the magnitude and direction of the displacement of the side rollers as well as by the length of the bearing block 6 necessary for reasons of strength.
It is an object of the present invention to so alter this known construction that the cost of the materials required and the space occupied may each be substantially reduced.